1. Technical Field
The present disclosure relates to a wiring board and a semiconductor device.
2. Description of the Related Art
As wiring boards for mounting electronic components such as semiconductor chips thereon, wiring boards having various shapes and structures have been proposed. For example, there has been known a wiring board which has a structure in which an internal wiring layer is centered, insulating layers are formed respectively on opposite upper and lower sides of the internal wiring layer, and via wirings formed respectively in the insulating layers are connected to the internal wiring layer (e.g. see JP-A-2011-134957). Lands for securing conduction to the respective via wirings on the opposite upper and lower sides are formed on the internal wiring layer.
In recent years, a demand for micronization and density increase of wirings in a wiring board on which a semiconductor chip can be mounted has risen in accordance with higher integration and higher functionality of the semiconductor chip. However, when each land of the internal wiring layer is formed to have a smaller planar shape and each via wiring is formed to have a smaller diameter in the aforementioned wiring board, connection reliability between the land and the via wiring may be lowered.